Such peristaltic pumps are particularly used in the area of medical technology, for example, as infusion pumps or in injection and dialysis devices. A generic peristaltic pump is known, for example, from patent AT 367874. It describes a peristaltic pump with several rollers driven by a central part via a planetary gear, in which the rollers, on at least one hose in which the medium to be conveyed is conducted, roll along its free cross-section while squeezing takes place. The rollers are supported in such a way that they can rotate on a rotating carrier with a large clearance and are in a friction-locking contact with at least one part of their circumference while they lie against the hose with the central part. The rotating movement of the carrier and the rollers causes the squeezed site to move along the hose, wherein the medium conducted in the hose is moved onward in the conveyance direction.
By the alternating squeezing, the hose is exposed to a considerable mechanical loading when the pump is running. Especially with the appearance of slack between the surface of the rollers and the hose surface, massive compression and shear forces appear, which stretch and pull the hose. With a high pressure, the hose can therefore be inflated or even destroyed. In order to largely spare the hose and to keep the adjusting effort during the introduction of the hose into the peristaltic pump as low as possible, a counterpressure body pressing the hose against at least one of the rollers is provided in the peristaltic pump known from AT 367874; it is kept on a base plate so it can be moved with respect to the central part of the peristaltic pump in the radial direction and is pretensioned by means of a spring in the direction of the central part. In this way, it is possible to merely place a new hose during the replacement of a hose and to already ensure a sufficient squeezing by the rollers during the pretensioning of the counterpressure body by means of a spring, so as to guarantee the functionality of the pump. Furthermore, tolerances in the pump arrangement and the hoses are compensated by the elastic counterpressure body.
This arrangement known from the state of the art has proved, however, to be susceptible to disruption because the springs that produce the pretensioning of the counterpressure body can lose their clamping force in the course of time or even break with material fatigue. The replacement of the springs, however, is cumbersome and time-consuming. Furthermore, the distance between the rollers and the counter bearing varies over their circumference, and the result is a low pump pressure.
Proceeding from this, the goal of the invention is to present a peristaltic pump, in which the production tolerances of the pump and the material nonuniformities of the hose are compensated as much as possible and the mechanical loading of the hose during the operation of the pump can be kept as low as possible, wherein, at the same time, as high as possible a pump pressure with a low loading of the hose and a handling of the peristaltic pump with the lowest maintenance possible is to be guaranteed. In particular, the effort to set and adjust the peristaltic pump during or immediately after its production and with regular maintenance is to be reduced.
These goals are attained with the peristaltic pump shown and described herein. Preferred embodiments of this peristaltic pump are also disclosed herein.